Device for vertical transport of goods

ABSTRACT

A machine for vertical transportation of goods from a packing line onto a pallet. The machine includes a vertically movable lifting device provided on a horizontally travelling wagon, the device being provided with lifting forks for receiving and lowering the pieces of packages. Counterweights are provided on the travelling wagon, the counterweights being connected to the lifting device by wires. The counterweights are heavier than the lifting device but the weight thereof is less than the total weight of the lifting device and the thereon loaded pieces of packages. The transmission comprises an endless loop, which is fixedly mounted to the lifting device, which is driven by a motor. During a cycle of operations the pieces of packages are fed from a packing line out onto the lifting forks of the machine until they abut a start impulse switch that starts the motor. Due to the weight of goods, the lifting forks are lowered until they are stopped by the pallet. Then the motor pulls the travelling wagon backwardly. In a rear position, the motor is reversed by a switch. Then, the lifting device provided with the lifting forks is drawn upwardly by the counterweights until it reaches a mechanical stop. The motor continues to be in operation and pulls the travelling wagon forwardly until it reaches a terminal position switch that stops the cycle of operations. The cycle of operations is repeated until the pallet has been loaded up to a desired level.

TECHNICAL FIELD

The present invention relates to an apparatus for vertical transport ofgoods, for instance transportation of pieces of packages from a packingline or a conveyor onto a pallet.

PRIOR ART

Devices for successively lowering a pallet as pieces of packages aremoved onto the pallet are previously known in connection with loading ofpallets. It is also previously known to use a lifting fork to lowerreceived pieces of packages down onto a pallet, which is not movedduring the operation. The previously known devices are often constructedin an unnecessarily complicated way both as far as the mechanical systemis concerned as well as concerning the control system. The previouslyknown devices of this type, as illustrated by the structures describedin Swedish patent specification No. 200.217 and DE OffenlegungsschriftNo. 26 20 535 are used for lowering pieces of packages from a conveyoronto a pallet. According to DE Offenlegungsschrift No. 26 20 535 theapparatus thereof is provided with lifting forks for receiving andlowering pieces of packages onto a pallet, and then specific wipers areused for wiping the pieces of packages off the lifting forks and ontothe pallet. For that cycle of operations three separate chaintransmissions are used, all driven by its own individual motor, and inone alternative one of said transmissions is replaced by a hydrauliccylinder.

A SHORT STATEMENT OF THE PRESENT INVENTION

The technical problem to be solved by the present invention relates tolowering pieces of packages from an upper level, for instance aconveyor, down to a lower level, for instance a pallet. This operationwas previously carried out either manually or by the aid of complicated,voluminous and expensive machines.

The above problem is solved in accordance with the present invention byusing one single transmission driven by one single motor for performingthe intended cycle of operations. An endless transmission belt or chainis used for co-operating with one single electrical motor for obtainingboth a horizontal and a vertical movement when the apparatus performs acycle of operations. Preferably, counterweights are used in order tobalance the weight of the lifting device according to the invention.

The advantages obtained by the present invention are among other thingsthat a relatively simple mechanical structure is obtained, that only aminimum force consumption is necessary, that an uncomplicated electricalcontrol system is used, which all result in a fail-safe and low energyconsuming machine having a very low total weight. When carefully chosingthe weights of the counterweights used in the machine in relation to theweight of the pieces of packages to be handled by the machine it ispossible to use a drive motor of a small size, which results in a lowenergy consuming structure.

DESCRIPTION OF THE FIGURES

FIG. 1 is illustrating in a schematic side elevational view a preferredembodiment of the device according to the invention, and

FIG. 2 is illustrating in a schematic top elevational view the deviceaccording to the invention as illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the invention is illustrated in the figuresand comprises a machine for loading pieces of packages from a packingline 15 down onto a pallet 17. The machine comprises a horizontallytravelling waggon 1 provided with a vertically movable lifting device 2having lifting forks 16 for receiving and lowering the pieces ofpackages. Counterweights 12 are arranged in connection with thehorizontally travelling waggon 1, said counterweights being connected bywires 11 to the vertically movable lifting device 2. By using saidcounterweights there is only need for a minimum effect to be used bothin connection with raising and lowering the lifting forks 16. Thetransmission means comprises in the preferred embodiment an endlesscogged belt 4, which is connected at 9 to the vertically movable liftingdevice 2 and is driven by one single small electrical motor 3.

In the beginning of an operation cycle the lifting forks 16 are locatedat the same level as the packing line 15 in a fixed position obtained bythe counterweights 12, a manually adjustable mechanical stop 14 and thecogged belt 4, which is braked to stand-still by the still standing(inoperative) electrical motor 3. The horizontally travelling waggon 1is standing in its forward-most position against a mechanical, resilientstop. The pieces of packages coming from the packing line 15 are fed outonto the lifting forks 16 of the machine and abut, when they are fedsufficiently far, a sensing pin connected to a starting impulse switch5. The starting impulse switch 5 is starting the electrical motor 3. Themotor 3 generates a constant, braking torque when the lifting forks 16of the vertically movable lifting device 2 are lowered, due to theweight of the pieces of packages loaded thereon down to a pallet 17located at a lower level. When the lifting forks 16 have reached andabut the pallet 17, or the wagon or the stacked goods, further verticalmovement of the forks is prevented and the vertically extending part ofthe cogged belt 4 is fixed relative to the wagon, the wagon thencontinuing in a horizontal direction. Then, the electrical motor 3,without changing its counterclockwise direction of rotation is, by theaid of the horizontally extending part of the cogged belt 4 pulling thehorizontally travelling waggon 1, backwardly from the pallet 17. Sincethe vertically movable lifting device 2 is mounted on the horizontallytravelling waggon 1 the lifting forks 16 do also move backwardly.However, the pieces of packages resting on the lifting forks 16 arestopped against support rolls 13, which in the preferred embodiment arefixedly mounted at the side of the lifting forks 16. When the liftingforks 16 are pulled away the pieces of packages will rest upon thepallet 17. The horizontally travelling waggon 1 will continue to bemoved backwardly by the motor until the tips of the lifting forks 16 aremoved into a position between the support rolls 13. Then, thehorizontally travelling waggon 1 is contacting a change-over switch 6,thereby reversing the rotation of the electrical motor 3.

The vertically movable lifting device 2 will then be pulled upwardly bythe aid of the counterweights 12 at a speed determined by the rotationalspeed of the electrical motor 3, which will act in a braking way duringthis movement. When the vertically movable lifting device 2 has reachedthe level of the packing line 15 it is stopped by a manually adjustablemechanical stop 14 and the vertically movable part of the cogged belt 4is fixed and the electrical motor 3 will, via the horizontally extendingpart of the cogged belt 4, draw the horizontally travelling waggon 1forwardly until it reaches a mechanical, resilient stop and a limitswitch 10, which both stops and reverses the polarity of the electricalmotor 3. The lifting forks 16 are now located at the packing line 15ready to receive new pieces of packages.

In the next cycle of operations the vertically movable lifting device 2and the lifting forks 16 thereof are lowered (supplied with pieces ofpackages) till they are stopped by the pieces of packages previouslyloaded on the pallet 17. The horizontally travelling waggon 1 will then,via the horizontally extending part of the cogged belt 4, be drawnbackwardly by the electrical motor 3. The pieces of packages will bestopped by the support rolls 13 and when the lifting forks 16 have beenmoved completely inside the space between said rolls the pallet 17 isloaded by two layers of pieces of packages.

In the above indicated way the loading operation will continue until thedesired top level has been reached.

At the top level there is provided a blocking switch 8 at the rearmostpart of the machine in such a way that it is contacted by a contact arm7 fixedly mounted on the vertically movable lifting device 2 and stopsthe electrical motor 3 when the lifting forks 16 are provided in abackward position.

Then, when the loaded pallet has been removed, either manually orautomatically, and been replaced by an empty pallet the machine mayagain be started, the lifting forks 16 will return to the startingposition at the packing line 15. If desired, also said startingoperation may be automatic.

MODIFIED EMBODIMENTS

Even though a presently preferred embodiment of the invention above hasbeen described with reference to the attached figures the personsskilled in the applicable art realize that the device may be modifiedwithin the frame of the accompanying claims. Hence, the motor has beenillustrated by an electrical motor even though it is possible to useanother driving source, such as a compressed air motor, which also canbe located at any place along the machine. The transmission belt hasbeen illustrated by a cogged belt, but of course, chains or wires mayalso be used alternatively. Of course, also the counterweights may bereplaced by force balancing blocks or resilient means, such as springmeans and the like, since the effect thereof is only to counterbalancethe weight of the vertically movable lifting device. The mentionedsupport rolls 13 may, of course, also be replaced by other suitablemeans for wiping off the pieces of packages onto the pallet orpreviously loaded layers of pieces of packages.

INDUSTRIAL USE

The present invention is useful in connection with any type of industrywherein packages, boxes, containers or other pieces of packages shouldbe transferred from an upper level, for instance a packing line or aconveyor, down to a lower level, for instance a pallet or a stack ofpreviously loaded pieces of packages. Since the invention provides asimple, cheap and reliable machine of a universally useful type theindustrial use thereof is extensive.

I claim:
 1. A machine for vertical transportation of goods from a feeding line onto a pallet by the aid of a vertically movable lifting device carried by a vertical guiding structure, said machine comprising:a base frame having a forward end and a rear end; a wagon horizontally movable on said base frame between a forward terminal stop and a rear terminal stop, said wagon carrying a vertical guide structure; an endless transmission loop element having two horizontal portions extending between forward and rear pullies fixed at said forward and rear ends of said frame respectively; one of said horizontal loop portions being branched into two vertical loop portions between a first pulley at the bottom of said guide structure onto and over a second pulley at the top of said guide structure and back to a third pulley at the bottom of said guide structure; a lifting device being vertically movable on said guide structure between said wagon and an upper stop at the top portion of said vertical guide structure, the lifting device being fixed to one of said vertical loop portions; a motor for driving said closed loop element to impart vertical displacement of the lifting device and horizontal displacement of the wagon by the intermediary of said closed transmission loop element; and an electrical control system controlling the horizontal and vertical displacements whereby the alteration between the vertical movement of the lifting device and the horizontal movement of the wagon being in response to the contact of the lifting device with at least one of the wagon, the pallet and goods on the pallet at one extreme and the stop at the other extreme to prevent movement of the vertical portion of the loop thereby causing horizontal movement of the wagon.
 2. A machine according to claim 1, wherein said motor is electrically powered and said endless transmission loop element is one of a toothed belt, a chain and a wire.
 3. A machine according to claim 2, further comprising counterweight means slidingly arranged on said vertical guiding structure and connected to the vertically movable lifting device by a wire element, said counterweight means being greater in weight than the total weight of the vertically movable lifting device, whereby said lifting device at the returning upward movement due to the weight of said counterweight means, firstly moves vertically towards a manually adjustable, mechanical stop located on said vertical guide structure and after hitting the stop, continuously moves horizontally towards a feeding line.
 4. A machine according to claim 3, wherein said electrical control system includes a starting impulse switch for starting the operating cycle of the motor by contact of a good from the feeding line with said starting impulse switch, a change-over contact switch for reversing the rotational direction of said electrical motor by contact of the lifting device with said change-over contact switch, and a terminal position switch for stopping the lifting device at a starting position near the feeding line.
 5. A machine according to claim 4, further comprising a vertically adjustable blocking switch arranged to be contacted by a contact arm fixedly mounted upon the vertically movable lifting device when said device has reached a predetermined load height of goods as determined by said blocking switch. 